Ported more Slic3r::GCode methods to XS

xs/t/21_gcode.t

@@ -0,0 +1,17 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Slic3r::XS;
+use Test::More tests => 2;
+
+{
+    my $gcodegen = Slic3r::GCode->new;
+    $gcodegen->set_origin(Slic3r::Pointf->new(10,0));
+    is_deeply $gcodegen->origin->pp, [10,0], 'set_origin';
+    $gcodegen->origin->translate(5,5);
+    is_deeply $gcodegen->origin->pp, [15,5], 'origin returns reference to point';
+}
+
+__END__